Themes are configured with $cfg['ThemeManager'] and
$cfg['ThemeDefault']. Under ./themes/, you should not
delete the directory pmahomme or its underlying structure, because this is
the system theme used by phpMyAdmin. pmahomme contains all images and
styles, for backwards compatibility and for all themes that would not include
images or css-files. If $cfg['ThemeManager'] is enabled, you
can select your favorite theme on the main page. Your selected theme will be
stored in a cookie.

在 4.8.0 版更改: Before 4.8.0 the theme metadata was passed in the info.inc.php file.
It has been replaced by theme.json to allow easier parsing (without
need to handle PHP code) and to support additional features.

In theme directory there is file theme.json which contains theme
metadata. Currently it consists of:

name

Display name of the theme.

This field is required.

version

Theme version, can be quite arbirary and does not have to match phpMyAdmin version.

This field is required.

desciption

Theme description. this will be shown on the website.

This field is required.

author

Theme author name.

This field is required.

url

Link to theme author website. It’s good idea to have way for getting
support there.

supports

Array of supported phpMyAdmin major versions.

This field is required.

For example, the definition for Original theme shipped with phpMyAdnin 4.8: